El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
$$\cos{\left(2 x + 3 \right)} = 0$$
Resolvermos esta ecuaciónPuntos de cruce con el eje X:
Solución analítica$$x_{1} = - \frac{3}{2} + \frac{\pi}{4}$$
$$x_{2} = - \frac{3}{2} + \frac{3 \pi}{4}$$
Solución numérica$$x_{1} = 82.537603483527$$
$$x_{2} = 90.3915851175014$$
$$x_{3} = 54.2632696012188$$
$$x_{4} = -5.42699081698724$$
$$x_{5} = 8.71017612416683$$
$$x_{6} = 77.8252145031423$$
$$x_{7} = -93.3915851175014$$
$$x_{8} = 55.8340659280137$$
$$x_{9} = -90.2499924639117$$
$$x_{10} = 3.99778714378214$$
$$x_{11} = 99.8163630782708$$
$$x_{12} = -69.829640215578$$
$$x_{13} = -17.9933614313464$$
$$x_{14} = 69.9712328691678$$
$$x_{15} = 85.6791961371168$$
$$x_{16} = 10.2809724509617$$
$$x_{17} = 16.5641577581413$$
$$x_{18} = 33.8429173528852$$
$$x_{19} = 27.5597320457056$$
$$x_{20} = -3.85619449019234$$
$$x_{21} = 32.2721210260903$$
$$x_{22} = 91.9623814442964$$
$$x_{23} = -2.28539816339745$$
$$x_{24} = -98.1039740978861$$
$$x_{25} = -11.7101761241668$$
$$x_{26} = -49.4092879672443$$
$$x_{27} = -39.984510006475$$
$$x_{28} = -33.7013246992954$$
$$x_{29} = 74.6836218495525$$
$$x_{30} = 71.5420291959627$$
$$x_{31} = 11.8517687777566$$
$$x_{32} = -46.2676953136546$$
$$x_{33} = -83.9668071567321$$
$$x_{34} = -61.9756585816035$$
$$x_{35} = 96.674770424681$$
$$x_{36} = -27.4181393921158$$
$$x_{37} = 40.1261026600648$$
$$x_{38} = -54.121676947629$$
$$x_{39} = -71.4004365423729$$
$$x_{40} = 63.6880475619882$$
$$x_{41} = 76.2544181763474$$
$$x_{42} = 68.4004365423729$$
$$x_{43} = -77.6836218495525$$
$$x_{44} = 2.42699081698724$$
$$x_{45} = 19.7057504117311$$
$$x_{46} = -57.2632696012188$$
$$x_{47} = 52.6924732744239$$
$$x_{48} = -19.5641577581413$$
$$x_{49} = -35.2721210260903$$
$$x_{50} = 41.6968989868597$$
$$x_{51} = -99.674770424681$$
$$x_{52} = -41.5553063332699$$
$$x_{53} = -91.8207887907066$$
$$x_{54} = -85.537603483527$$
$$x_{55} = -82.3960108299372$$
$$x_{56} = -24.276546738526$$
$$x_{57} = 25.9889357189107$$
$$x_{58} = 62.1172512351933$$
$$x_{59} = -32.1305283725005$$
$$x_{60} = 24.4181393921158$$
$$x_{61} = 60.5464549083984$$
$$x_{62} = -47.8384916404494$$
$$x_{63} = -68.2588438887831$$
$$x_{64} = 38.5553063332699$$
$$x_{65} = 5.56858347057703$$
$$x_{66} = 46.4092879672443$$
$$x_{67} = -13.2809724509617$$
$$x_{68} = -21.1349540849362$$
$$x_{69} = 98.2455667514759$$
$$x_{70} = -10.1393797973719$$
$$x_{71} = 84.1083998103219$$
$$x_{72} = 104.528752058656$$
$$x_{73} = -60.4048622548086$$
$$x_{74} = 146.940252882118$$
$$x_{75} = -16.4225651045515$$
$$x_{76} = -76.1128255227576$$
$$x_{77} = -38.4137136796801$$
$$x_{78} = 49.5508806208341$$
$$x_{79} = 93.5331777710912$$
$$x_{80} = -25.8473430653209$$
$$x_{81} = -63.5464549083984$$
$$x_{82} = 47.9800842940392$$
$$x_{83} = 30.7013246992954$$
$$x_{84} = -55.6924732744239$$
$$x_{85} = 18.1349540849362$$
$$x_{86} = -79.2544181763474$$